Natural Selections: Phenotypes vs. Genotypes

Natural Selections: Phenotypes vs. Genotypes

  • Submitted By: myabshurt
  • Date Submitted: 11/14/2010 11:46 AM
  • Category: Science
  • Words: 494
  • Page: 2
  • Views: 396

7a. Students know why natural selection acts on the phenotype rather than the genotype of an organism.
A: When organisms are attracted to a potential mate it matters on the phenotype and not the genotype.
For example: Female swallows only go for the looks and try to find a male swallow with a dark red color on their chest. If they find one that is red and see another one that is darker they leave the current male for the darker one.

7b. Students know why alleles that are lethal in a homozygous individual may be carried in a heterozygote and thus maintained in a gene pool.
B: Lethal alleles may also have a positive side to them if they are heterozygous. For example, sickle cell anemia, if they have a heterozygous allele for it then they carry it but don’t have it and instead they can’t get Malaria.

7c. Students know new mutations are constantly being generated in a gene pool.
C: Organisms enter and leave their population and mix with another population creating something different in the population. For example, if a yellow bug leaves their population and enters are brown bug population the yellow bug is changing thing in the brown population.

7d. Students know variation within a species increases the likelihood that at least some members of a species will survive under changed environmental conditions.
D: Some organisms are made to live under certain environmental conditions. For example, a bird with a short beak can’t get food with it is deep down a hole but one with a long narrow beak can.

8a. Students know how natural selection determines the differential survival of groups of organisms.
A: When organisms blend into the background so they will be less noticed. For example, a peppered moth, there are two type of them one blends into the tree bark and the other blends into the dark bark at night. Both can be less seen but it depends on the time of day.

8b. Students know a great diversity of species...

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